diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index aa21a151bc..bb025301ab 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -270,7 +270,7 @@ class Field(RegisterLookupMixin):
                     break
                 if self.max_length is not None and group_choices:
                     choice_max_length = max(
-                        choice_max_length,
+                        choice_max_length, 0,
                         *(len(value) for value, _ in group_choices if isinstance(value, str)),
                     )
             except (TypeError, ValueError):
